1. Field of the Invention
The present invention relates to a digital broadcast signal, and more particularly, to a digital broadcast signal, a digital television receiver and method of processing digital broadcast signal.
2. Discussion of the Related Art
In digital broadcast, a program and system information protocol (hereinafter referred to as “PSIP”) is a protocol used for tuning channels and transmitting program schedules in an advanced television systems committee (ATSC), which is a digital broadcast standard in a terrestrial and cable digital broadcast environment. More specifically, the PSIP is a standard protocol for transmitting tables which are included in packets transmitted by a multiplexed transport stream. Herein, a plurality of tables each having a specific object (or purpose) is defined in the PSIP. Basically, the tables are structured in sections, such as the table defined in a program system information (PSI) of moving picture expert group (MPEG) data. In other words, each table of the PSIP is formed to have a section structure in order to be transmitted. Herein, depending upon the table type, each table may be configured in a single section or a plurality of sections.
The tables of the PSIP include a virtual channel table (VCT), a system time table (STT), a master guide table (MGT), a rating region table (RRT), an event information table (EIT), and an extended text table (ETT). More specifically, the VCT provides information on a virtual channel, and the STT provides information on the current date and time. The MGT includes a packet identifier (PID) value and version number for each of the PSIP table except for the STT. The RRT provides rating information related to the contents of the program. The EIT provides information on the title and starting time of a program for all channels within the VCT during at least 3 hours. And, the ETT provides detailed description on the background, synopsis, characters, and so on, of a particular program.
Among the above-described tables, the RRT provides program rating information related to several regions. Herein, each RRT defined in accordance with the program rating information includes rating system information of a particular region. Furthermore, the RRT is a standard table of a ‘Content_Advisory_Descriptor’, which indicates event schedules and program ratings existing in the EIT or the PMT, wherein information of each event is included.
However, the related art digital broadcast signal including the RRT, and the method and apparatus for processing the same have the following advantages. The digital broadcast signal only includes RRTS having fixed rating information. Thus, downloadable RRTs are not supported. Therefore, a method and apparatus for receiving and processing the digital broadcast signal cannot be realized. Furthermore, if the RRT is downloadable, the receiver should determine which of the RRTs received by each channel is the most recent version and, therefore, valid, by checking the version number. However, since there are no specific standard, it is difficult to make such determination in the related art.